/*  mbed Microcontroller Library
    Copyright (c) 2006-2013 ARM Limited

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
#ifndef MBED_SPISLAVE_H
#define MBED_SPISLAVE_H

#include "platform.h"

#if DEVICE_SPISLAVE

#include "spi_api.h"

namespace mbed {

    /** A SPI slave, used for communicating with a SPI Master device

        The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz

        Example:
        @code
        // Reply to a SPI master as slave

        #include "mbed.h"

        SPISlave device(p5, p6, p7, p8); // mosi, miso, sclk, ssel

        int main() {
           device.reply(0x00);              // Prime SPI with first reply
           while(1) {
               if(device.receive()) {
                   int v = device.read();   // Read byte from master
                   v = (v + 1) % 0x100;     // Add one to it, modulo 256
                   device.reply(v);         // Make this the next reply
               }
           }
        }
        @endcode
    */
    class SPISlave {

      public:

        /** Create a SPI slave connected to the specified pins

            mosi or miso can be specfied as NC if not used

            @param mosi SPI Master Out, Slave In pin
            @param miso SPI Master In, Slave Out pin
            @param sclk SPI Clock pin
            @param ssel SPI chip select pin
        */
        SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);

        /** Configure the data transmission format

            @param bits Number of bits per SPI frame (4 - 16)
            @param mode Clock polarity and phase mode (0 - 3)

            @code
            mode | POL PHA
            -----+--------
             0  |  0   0
             1  |  0   1
             2  |  1   0
             3  |  1   1
            @endcode
        */
        void format(int bits, int mode = 0);

        /** Set the spi bus clock frequency

            @param hz SCLK frequency in hz (default = 1MHz)
        */
        void frequency(int hz = 1000000);

        /** Polls the SPI to see if data has been received

            @returns
              0 if no data,
              1 otherwise
        */
        int receive(void);

        /** Retrieve  data from receive buffer as slave

            @returns
              the data in the receive buffer
        */
        int read(void);

        /** Fill the transmission buffer with the value to be written out
            as slave on the next received message from the master.

            @param value the data to be transmitted next
        */
        void reply(int value);

      protected:
        spi_t _spi;

        int _bits;
        int _mode;
        int _hz;
    };

} // namespace mbed

#endif

#endif
